Using Air Quality Modelling to Improve Air Emission Inventories

Today emission inventories are one of the key components of air quality management. For instance, inventories are supportive for: the modelling of atmospheric pollutants; the process of compliance verification of national emission obligations; and the establishment of baseline scenarios for the development and monitoring of the policies and measures. Therefore, emission inventories should be developed accordingly to high reliable standards and should be validated using appropriate methodologies, guaranteeing that they appropriately may be used to predict air quality when coupled to models. In Europe, one of the main goals of national inventories has been to verify that countries are complying with their international commitments at national level, such as those set by UNFCCC and the Kyoto Protocol; CLRTAP and UE-NEC Directive; and the Stockholm Convention. In Portugal, efforts were also been made to integrate the total emission estimates at national level, with estimates made for a detailed level of spatial allocation of emissions, and using a suitable temporal disaggregation of emissions. In order to conclude for the best disaggregation level to be used to the Portuguese national system, an air quality modelling system was used to tested several emission inventories resolution schemes available for Portugal (INERPA, EMEP and LOTOS) and further disaggregation schema at sub-municipal level. Evaluations were done using the CHIMERE model, forced by the MM5 meteorological fields, over the Portuguese domain. Results from this exercise show the existence of discrepancies between different disaggregation instances for emission inventories. Different temporal profiles were also tested, indicating that there this has strong influence on results, and confirming that the use of average European profiles may not be appropriate at national nor regional level. The results of this analysis lead to the improvement of emission inventories in Portugal and the quality of results from air quality models